No sooner have we had a splurge of publicity around Bill Pott’s sexuality (Pearl Mackie’s Bill Potts will be Doctor Who’s first openly gay companionPearl Mackie’s Bill Potts will be Doctor Who’s first openly gay companion) than we have speculation she may not survive Peter Capaldi’s departure from the series. If true (and it may well be) it rather pulls the rug away from investing too far in her character.
My instinct is towards having a companion overlap two Doctors, though perhaps the audience doesn’t need that any more. I decided to think about it further…

Regeneration companions

I thought a table to capture my thoughts:

So what does this tell us? Well in only around half the regenerations did viewers have a continuing character to support. The first regeneration at the end of Tenth Planet needed continuity for the sake of the show, and in some cases the companions went quickly (eg Ben, Polly, Sarah Jane) while in others they had their best adventures with the newer Doctor (eg Adric, Nyssa, Tegan).

As a device I’d prefer it if Bill survived to work with the next Doctor, and it gives some easy ‘you’ve changed’ dynamics. If I look at the last show-runner change, it is more than likely Chris Chibnall will get a blank slate. Sadly this will mean Pearl Mackie only gets one run to impress (until Big Finish grabs her;-).